GROUND OF INDUCTION. 377 



the instances are few or many, -conclusive or incon- 

 clusive, does not much affect the matter : these are 

 considerations which occur only on reflexion :- the 

 unprompted tendency of the mind is to generalize its 

 experience, provided this points all in one direction ; 

 provided no other experience of a conflicting character 

 comes unsought. The notion of seeking it, of expe- 

 rimenting for it, of interrogating nature (to use 

 Bacon's expression,) is of much later growth. The 

 observation of nature, by uncultivated intellects, is 

 purely passive : they take the facts which present 

 themselves, without taking the trouble of searching 

 for more : it is a superior mind only which asks 

 itself what facts are needed to enable it to come to a 

 sure conclusion, and then looks out for these. 



But although we have always a propensity to 

 generalize from unvarying experience, we are not 

 always warranted in doing so. Before we can be at 

 liberty to conclude that something is universally true 

 because we have never known an instance to the 

 contrary, it must be proved to us that if there were 

 in nature any instances to the contrary, we should 

 have known of them. This assurance, in the great 

 majority of cases, we cannot have, or can have only in 

 a very moderate degree. The possibility of having 

 it, is the foundation on which we shall see hereafter 

 that induction by simple enumeration may in some 

 remarkable cases amount to full proof*. No such 

 assurance, however, can be had, on any of the ordi- 

 nary subjects of scientific inquiry. Popular notions 

 are usually founded upon induction by simple enume- 

 ration ; in science it carries us but a little way. We 

 are forced to begin with it ; we must often rely upon 



* Infra, chap. xxi. xxii. 



